KR100465880B1 - Process of the Thermoplastic Resin with High Tensile Strength and High Fluidity - Google Patents

Abstract

The high rigidity thermoplastic resin of the present invention is the total flow rate of the styrene monomer is introduced into the first and second reactors in the first reactor, F, the total flow rate is introduced into the first reactor, F ₁ , the total flow rate to the second reactor F ₂ , when the reactor volume of the first reactor is V ₁ and the volume of the reaction solution in the first reactor is V ₁ ′, F = F ₁ + F _2, 5.6 ≤ F ₁ / F ₂ ≤ 6.6, 1.8 ≦ V ₁ / V ₁ ′ ≦ 2.1; When the contents of the reactor in the second reactor are V ₂ and the contents of the reaction solution in the second reactor are V ₂ ′, 2.2 ≤ V ₂ / V ₂ '≤ 3.3, F = F ₁ + F ₂ Continuous bulk polymerization was carried out by continuously adding 0.3 to 1.2% by weight of a hydrocarbon compound on the basis of a final pellet under the condition of; Then, the unreacted monomer is separated from the polymer produced from the second reactor and then cut into pellets. The average molecular weight is 230,000 to 300,000, and the yellowness is 1.0 or less.

Description

Process of manufacturing the high flow high rigidity thermoplastic resin {Process of the Thermoplastic Resin with High Tensile Strength and High Fluidity}

Field of invention

The present invention relates to a method for producing a high rigid thermoplastic resin. More specifically, the present invention controls the reaction conditions in the first reactor to significantly increase the residence time, in the second reactor to adjust the reaction conditions to reduce the low temperature maintenance and reaction time solid mass by polystyrene continuous polymerization (polystyrene) By producing a thermoplastic resin having a certain range of content and a molecular weight in a specific range, the yellowness is good, the releasability is excellent, and the rigidity is greatly improved, such as an audio tape case, a food and beverage container, a biaxially stretched polystyrene, and the like. The present invention relates to a method for producing a highly rigid thermoplastic resin useful for the preparation of a resin.

Background of the Invention

In general, high rigid polystyrene has been used in the manufacture of audio tape cases, food and beverage containers. Conventional techniques for producing such high rigid polystyrene include a plurality of reactors, the manufacturing process proceeds to solution polymerization, and all the raw material solution is introduced into the first reactor to polymerize, the methods are Japan and the United States Many are known through patent documents.

However, by the above method, high rigidity polystyrene having a high molecular weight can be obtained, but there are disadvantages in that a large number of reactors not only decreases productivity, but also increases the amount of defects when varieties are replaced. In addition, since the reaction is carried out by solution polymerization using solvents (EB, MEK), polystyrene, which has transparency as the best condition, brings about lowering of the product.

In order to solve the problems of the prior art, the present inventors have developed a method for producing a high molecular weight polystyrene resin having good yellowness and excellent rigidity by continuous bulk polymerization in two reactors.

An object of the present invention is to provide a method for producing a thermoplastic resin excellent in rigidity.

Another object of the present invention is to provide a method for producing a highly rigid thermoplastic resin useful in the manufacture of an audio tape case, a food and beverage container, a biaxially stretched polystyrene, and the like, as well as excellent yellowness and excellent releasability.

Both the above and other objects of the present invention can be achieved by the present invention described below. Hereinafter, the content of the present invention will be described in detail.

1 is a schematic diagram schematically showing a continuous block polymerization apparatus for producing a highly rigid thermoplastic resin according to the present invention.

Brief description of the main symbols in the drawing

1: total flow rate (F) in which styrene monomer is introduced into the first and second reactors

2: total flow rate of the styrene monomer to the first reactor (F ₁ )

3: total flow rate of the styrene monomer to the second reactor (F ₂ )

4: reactor content of the first reactor (V ₁ )

5: the volume of the reaction solution in the first reactor (V ₁ ')

6: reactor volume of the second reactor (V ₂ )

7: Content (V ₂ ') of the reaction solution in the second reactor

Summary of the Invention

Highly rigid thermoplastic resin of the present invention is a mass polymerization of the styrene monomer (raw material solution) in the first reactor and the second reactor in the production of polystyrene, by adjusting the ratio of the total injection flow rate of the styrene monomer and the first reactor It is prepared by separating the second reactor.

In the first reactor, a core reaction for producing high molecular weight polystyrene, which is a condition for producing styrene monomer into a high rigid resin, is performed. In the second reactor, low molecular weight polystyrene is suppressed in the reactants of the first reactor that is continuously moved. In addition, hydrocarbon compounds extracted from petroleum are added to give additional reaction to increase the ratio of the final solid content and to give excellent release property in molding the resin.

The high rigid thermoplastic resin according to the present invention is subjected to continuous bulk polymerization while maintaining the styrene monomer input flow rate and reaction time in the first reactor under the conditions of the following formulas (A) to (C); Continuous block polymerization while maintaining the reaction conditions in the second reactor under the conditions of the following formula (D); And by separating the unreacted monomer from the polymer (solids) produced in the second reactor:

F = F ₁ + F ₂ (A)

5.6 ≤ F ₁ / F ₂ ≤ 6.6 (B)

1.8 ≤ V ₁ / V ₁ '≤ 2.1 (C)

2.2 ≤ V ₂ / V ₂ '≤ 3.3 (D)

In the above formula, F is the total flow rate of the styrene monomer to the first, second reactor, F ₁ is the total flow rate of the styrene monomer to the first reactor, F ₂ is the total flow rate of the styrene monomer to the second reactor. Flow rate, V ₁ is the reactor content of the first reactor, V ₁ ′ is the content of the reaction liquid in the first reactor, V ₂ is the reactor content of the second reactor, and V ₂ ′ is the reaction in the second reactor. It is the amount that the amount occupies.

In the production method according to the present invention, the continuous block polymerization is performed at 115 to 125 ° C. in the first reactor, and the continuous block polymerization is performed at 135 to 155 ° C. in the second reactor. The content of polystyrene obtained by the above method is 55 to 70% by weight in the second reactor on a solids basis, the average molecular weight of the final pellet resin is 23 to 300,000, the yellowness is 1.0 or less.

Detailed Description of the Invention

Hereinafter, a method of manufacturing the high rigid thermoplastic resin of the present invention will be described in detail.

First, in the first reactor and the second reactor, the styrene monomer is continuously supplied from the tank in which the styrene monomer is stored. Styrene monomers that can be used in the present invention include styrene; side chain alkyl-substituted styrenes such as α-ethylstyrene and α-methylstyrene; Nuclear alkyl substituted styrenes such as vinyl xylene, O-t-butylstyrene, P-t-butylstyrene and P-methyl styrene; Halogenated styrenes such as monochloro styrene, dichloro styrene, tribromo styrene and tetrahydro styrene; P-hydroxy styrene; And O-methoxy styrene. Of these, styrene is most commonly used.

(1) Polymerization in the first reactor

The total flow rate of the raw material solution (styrene monomer) to the first and second reactors is F, the total flow rate of the raw material solution to the first reactor is F ₁ , and the total flow rate of the raw material solution to the second reactor is F _2. , F = F ₁ + F _2, 5.6 ≤ F ₁ / F ₂ ≤ 6.6, 1.8 ≤ V when the reactor content of the first reactor is V ₁ , and the volume of the reaction solution in the first reactor is V ₁ ′. _Under the condition of ₁ / V ₁ '≤ 2.1, the stirrer rotational speed of the first reactor was adjusted to 30 times / min to continuously bulk polymerize at 115 to 125 ° C.

In the case of F ₁ / F ₂ > 6.6, high molecular weight polystyrene cannot be formed, and in the case of F ₁ / F ₂ <5.6, the viscosity of the reactants is too high, resulting in poor transport, making it difficult to control the temperature of the second reactor. However, a large amount of low molecular weight polystyrene is generated in the second reactor, so that the desired high rigid resin cannot be obtained. In addition, the reason for maintaining the conditions of 5.6 ≤ F ₁ / F ₂ ≤ 6.6, F = F ₁ + F _{2 in} the _first reactor is to effectively control the viscosity using the two reactors, to facilitate the transfer of the reactants, It is for the high molecular weight styrene resin to have high rigidity.

In the case of V ₁ / V ₁ '> 2.1, the viscosity becomes too high and the load of the stirrer increases, making it difficult to operate and also endangering the lack of time to cope with emergencies. On the other hand, in the case of V ₁ / V ₁ '<1.8, the solid content of the desired content cannot be obtained, and the molecular weight is lowered to obtain a high molecular weight resin.

As a result, by maintaining the reaction conditions in the first reactor, it is possible to transfer the reactants smoothly in the continuous bulk polymerization without using a solvent, and a high rigidity high molecular weight resin having an average molecular weight of 23 to 300,000 can be obtained.

The polymerized product in the first reactor is continuously supplied to the second reactor and subjected to continuous bulk polymerization.

(2) Polymerization in Second Reactor

The total flow rate of the raw material solution (styrene monomer) to the first and second reactors is F, the total flow rate of the raw material solution to the first reactor is F ₁ , and the total flow rate of the raw material solution to the second reactor is F _2. When the content of the reactor in the second reactor is V ₂ , and the content of the reaction solution in the second reactor is V ₂ ′, the conditions of 2.2 ≦ V ₂ / V ₂ '≤ 3.3, F = F ₁ + F ₂ The reactor is fixed at 20 revolutions per minute, and subjected to continuous bulk polymerization at 135 to 155 캜 so that the solid content is 55 to 70 wt%. In addition, 0.3 to 1.2% by weight of the hydrocarbon compound is continuously added to the final pellets.

Hydrocarbon compounds usable in the present invention are generally referred to as white oil.

In the second reactor, in the case of V ₂ / V ₂ '> 3.3, the content of solids decreases and productivity decreases. In the case of V ₂ / V ₂ '<2.2, low molecular weight production increases, so that high rigidity resin cannot be obtained and calorific value It is difficult to control the polymerization temperature due to increase.

Maintaining the temperature below 135 ° C. in the second reactor results in a decrease in productivity. When the temperature is maintained above 156 ° C., a high molecular weight generation rate is low, and thus a desired high rigid resin cannot be obtained.

Therefore, the reaction conditions of the second reactor are maintained at 2.2 ≦ V ₂ / V ₂ ′ ≦ 3.3, F = F ₁ + F ₂ , 135-155 ° C., and 0.3 to 1.2% by weight of the hydrocarbon compound is continuously added. A high molecular weight polystyrene excellent in rigidity can be obtained while maintaining productivity.

Other additives, such as molecular weight modifiers, may be added to the first reactor or the second reactor, which can be readily performed by one skilled in the art. For example, an antistatic agent, antioxidant, etc. can be added and used suitably according to each use.

After the polymerization reaction is completed in the second reactor, an unreacted monomer is separated through a temperature riser, a volatilization tank, and the like, and is then cut into pellets. The average molecular weight of this pellet-form final resin is 230,000-300,000, and yellowness is 1.0 or less.

According to the production method of the present invention, high transparency polystyrene having good transparency and maintaining high rigidity characteristics is efficiently manufactured using two reactors without additional solvent addition.

The invention can be better understood by the following examples, which are intended for the purpose of illustration of the invention and are not intended to limit the scope of protection defined by the appended claims.

Example

Example 1

In the first reactor, the polymerization is carried out in which the total flow rate of the raw material solution (styrene monomer) into the first and second reactors is F, the total flow rate of the raw material solution into the first reactor is F ₁ , and the raw material solution is introduced into the second reactor. F = F ₁ + F _2, F ₁ / F ₂ = 6.1 when the total flow rate is F ₂ , the reactor content of the first reactor is V ₁ , and the volume of the reaction solution in the first reactor is V ₁ ′. , V ₁ / V ₁ ′ was carried out under the reaction conditions of 1.95. Continuous bulk polymerization was carried out at an agitator speed of 30 times / min and a polymerization temperature of 120 ° C.

The polymer of the first reactor is continuously supplied to the second reactor in the same manner as the supply flow rate of the first reactor, so that the total flow rate of the raw material solution (styrene monomer) into the first and second reactors is F, and the raw material solution is the first reactor. The total flow rate introduced into the reactor F ₁ , the total flow rate of the raw material solution into the second reactor, F ₂ , the reactor volume of the second reactor V ₂ , and the volume of the reaction solution in the second reactor V ₂ ′. At that time, V ₂ / V ₂ ′ = 2.5, F = F ₁ + F ₂ was maintained. The rotation speed of the reactor was fixed at 20 times / minute, and the reaction temperature was maintained at 146 ° C.

In the second reactor, white oil, a hydrocarbon compound extracted from petroleum, was continuously added in a separate storage tank so as to be 0.6% by weight in the final pellet.

The final polymer obtained in the second reactor was continuously sent to a devolatilization step and heated up to 245 ° C. to remove volatile components such as unreacted monomers. The molecular weight, yellowness, and tensile strength of the resin on the obtained pellets were measured, and the releasability evaluation was performed using the lattice mold of the injection machine.

Tensile strength was measured at a rate of 20 mm / min according to ASTM D638.

Yellowness was measured by JIS K7105.

Molecular weight is 5 mg of the sample in the final pellet, 5 ml of THF is mixed in a shaker and shaken for 30 minutes to completely dissolve the solution, and then the solution is subjected to gel permeation chromatography of SPECTRA-PHYSICS ANALYTICAL. Measured.

The release cracking rate was calculated by converting 20 crack generation rates into a 5.3 OZ injection machine manufactured by Venus Cable using a lattice mold for evaluation of release property.

Example 2

F ₁ / F ₂ = was conducted in the same manner as in Example 1 except changing 6.5.

Example 3

The same procedure as in Example 1 was carried out except that the residence time of the first reactor was adjusted to V ₁ / V ₁ ′ = 2.05.

Example 4

The same procedure as in Example 1 was conducted except that the residence time of the second reactor was adjusted to V ₂ / V ₂ ′ = 3.1.

Example 5

The same process as in Example 1 was conducted except that the temperature of the second reactor was changed to 152 ° C.

Example 6

The same procedure as in Example 1 was conducted except that the white oil continuously added to the second reactor was adjusted to 1.1 wt%.

Comparative Example 1

The reaction was carried out in the same manner as in Example 1, except that the reaction rate of the raw material solution (styrene monomer) was adjusted to F ₂ = 0.

Comparative Example 2

The same procedure as in Example 1 was performed except that the residence time of the first reactor was adjusted to V ₁ / V ₁ ′ = 2.30.

Comparative Example 3

The same procedure as in Example 1 was carried out except that the residence time of the second reactor was adjusted to V ₂ / V ₂ ′ = 1.9.

Comparative Example 4

The same process as in Example 1 was conducted except that the temperature of the second reactor was changed to 165 ° C.

Comparative Example 5

The same procedure as in Example 1 was conducted except that no white oil was added to the second reactor.

Comparative Example 6

The same procedure as in Example 1 was conducted except that the white oil continuously added to the second reactor was adjusted to 1.5 wt%.

Tables 1 and 2 show the measurement results of the physical properties of the resins prepared according to the examples and the reaction conditions used in Examples 1 to 6 and Comparative Examples 1 to 6, respectively.

Example One 2 3 4 5 6 Reaction condition F ₁ / F ₂ 6.1 6.5 6.1 6.1 6.1 6.1 V ₁ / V ₁ '' 1.95 1.95 2.05 1.95 1.95 1.95 V ₂ / V ₂ '' 2.5 2.5 2.5 3.1 2.5 2.5 Hydrocarbon compound (wt%) 0.6 0.6 0.6 0.6 0.6 1.1 Second reactor temperature (℃) 146 146 146 146 152 146 Properties Average molecular weight (Mw x 1,000) 250 270 240 280 290 250 Tensile Strength (㎏ / ㎠) 500 510 500 520 530 495 Yellow Degree (YI) 0.9 0.8 0.9 0.7 0.9 0.9 Release Breakage Rate (%) 2 One 2 2 One One

Comparative Example One 2 3 4 5 6 Reaction condition F ₁ / F ₂ F ₂ = 0 6.1 6.1 6.1 6.1 6.1 V ₁ / V ₁ '' 1.95 2.30 1.95 1.95 1.95 1.95 V ₂ / V ₂ '' 2.5 2.5 1.9 2.5 2.5 2.5 Hydrocarbon compound (wt%) 0.6 0.6 0.6 0.6 0 1.5 Second reactor temperature (℃) 146 146 146 165 146 146 Properties Average molecular weight (Mw x 1,000) 200 210 220 215 250 250 Tensile Strength (㎏ / ㎠) 450 440 460 455 490 480 Yellow Degree (YI) 1.3 0.9 0.7 1.5 0.9 0.9 Release Breakage Rate (%) 10 12 11 13 6 5

From the results of Tables 1 and 2, it can be seen that a high molecular weight polystyrene resin having excellent yellowness, release property and rigidity can be obtained by continuous bulk polymerization under the reaction conditions according to the present invention.

The present invention has the effect of providing a high-strength thermoplastic resin that is useful in the manufacture of audio tape cases, food and beverage containers, biaxially stretched polystyrene, and the like, as well as excellent yellowness and excellent releasability.

Simple modifications or changes of the present invention can be easily carried out by those skilled in the art, and all such modifications or changes can be seen to be included in the scope of the present invention.

Claims (3)

The total flow rate of the styrene monomer to the first and second reactors in the first reactor is F, the total flow rate to the first reactor is F ₁ , the total flow rate to the second reactor is F ₂ , and the reactor of the first reactor "when _{called, F = F 1 + F 2} , 5.6 ≤ F 1 / F 2 ≤ 6.6, 1.8 ≤ V 1 / V 1 ' contents information fewer reaction solution points in V _1, a first reactor enemy V ₁ ≤ Continuous block polymerization under the condition of 2.1; When the contents of the reactor in the second reactor are V ₂ and the contents of the reaction solution in the second reactor are V ₂ ′, 2.2 ≤ V ₂ / V ₂ '≤ 3.3, F = F ₁ + F ₂ Continuous bulk polymerization was carried out by continuously adding 0.3 to 1.2% by weight of a hydrocarbon compound on the basis of the final pellets under the condition of; And Separating the unreacted monomer from the polymer produced from the second reactor and then cutting into pellets; A method for producing a highly rigid thermoplastic resin having an average molecular weight of 23 to 300,000 and a yellowness of 0.1 to 1.0, characterized by being produced by the step. The method of claim 1, wherein the temperature of the first reactor is maintained at 115 to 125 ° C and the temperature of the second reactor is maintained at 135 to 155 ° C. The method for producing a highly rigid thermoplastic resin according to claim 1, wherein the hydrocarbon compound is a white oil.